sesquipedalian: [17] Sesquipedalian means etymologically ‘a foot and a half long’. Its use in English was inspired by the Roman poet Horace’s phrase sesquipedalia verba, literally ‘words a foot and a half long’, hence ‘preposterously long words that sound pompous’ – of which sesquipedalian itself is an appropriately good example. It is a compound word formed from the Latin prefix sesqui- ‘half as much again’ (a derivative of sēmi- ‘half’) and pēs ‘foot’. => foot, pedal
1610s, "person or thing a foot and a half long," from Latin sesquipedalia "a foot-and-a-half long," from sesqui- "half as much again" (see sesqui-) + stem of pes "foot," from PIE root *ped- (1) "a foot" (see foot (n.)). As an adjective 1650s. Meaning "sesquipedalian word" (1830) is from Latin sesquipedalia verba "words a foot-and-a-half long," in Horace's "Ars Poetica" (97), nicely illustrating the thing he is criticizing.
